Armrests are an important feature for me as well - those cars that have seats without armrests invariably have something else that is designed for you to rest your arms on instead - usually the door trim / handle on one side, and a centre cubby box of some description on the other side. There is unlikely to be anything equivalent in a bus, so having a seat without armrests would be unthinkable for me. The armrests invariably fold up to be out of the way when not required, or if they were found to be in the way when frequent gear changes are required.